Fully automatic 10 A digital micro-ohmmeter for resistances from 0.01 µΩ to 200 Ω, in the field and in the laboratory
Measuring contact resistances, joints and grounding connections of a few micro-ohms calls for a four-wire micro-ohmmeter with sub-micro-ohm resolution, enough test current and a size that can be taken into the field. The PDRM-10A measures from 0.01 µΩ to 200 Ω with 0.01 µΩ resolution and ±0.1% ±2 digits accuracy on all scales, selects the 5 mA, 250 mA or 10 A DC test current by itself and uses the four-wire Kelvin method with input channels filtered against strong magnetic fields; weighing 0.86 kg, it performs over 12,000 measurements at 10 A per charge.
PDRM-10A key data
- Range and resolution: 0.01 µΩ to 200 Ω over 8 scales, from 20 µΩ to 200 Ω, with automatic selection; 0.01 µΩ resolution.
- Accuracy: the PDRM-10A measures with ±0.1% of reading ±2 digits on each of its 8 scales.
- Test current: 5 mA, 250 mA or 10 A DC, selected automatically; the low current allows measurement on small measuring contacts.
- Measurement method: four-wire Kelvin, with the voltage electrodes inside the current electrodes; a microprocessor compensates for thermocouples and parasitic voltages, and the filtered input channels allow measurement in strong magnetic fields. Standard and differential modes.
- Autonomy: 6 rechargeable AA NiMH batteries, 1.2 V, 2.1 Ah: over 12,000 measurements at 10 A and over 10,000 at the other currents; automatic shutdown after 2 minutes.
- In the field: 0.86 kg and 203 × 114 × 51 mm; operation from -20°C to 50°C, storage from -40°C to 50°C and 0 to 95% humidity, non-condensing; 128 × 64 pixel backlit LCD.
- PDRM-10A accessories: exothermic weld probe, two-hand probes with spring-loaded tips, 35 mm booster-type and 19 mm dolphin-type clamps, duck-elbow grounding accessory and 9.5 µΩ reference resistance.
Advantages
Class-leading resolution
It measures resistances from 0.01 µΩ to 200 Ω with a resolution of 0.01 µΩ and automatic selection of the injection current between 5 mA and 10 A, adapting to each type of contact.
Four-wire Kelvin method with advanced filtering
Current injection and voltage measurement are carried out through independent circuits, removing the influence of cable resistance. An internal microprocessor compensates for thermocouples and parasitic voltages, and the heavily filtered input channels allow reliable measurement near strong magnetic fields.
Lightweight, rugged design
Weighing 860 g and measuring 203 × 114 × 51 mm, it operates between -20°C and 50°C and suits continuous use in the workshop or outdoors, with a backlit LCD display.
Long battery life and a wide choice of probes
Its rechargeable NiMH batteries allow for more than 12,000 measurements at 10 A, and it accepts a broad range of interchangeable clamps and probes for different contact types.
Applications
- Quality control of castings and verification of arc and exothermic welds.
- Electrode control in aluminium plants and other industrial facilities.
- Inspection of contacts, switches and fuses in electrical maintenance programmes.
- Verification of grounding connections and other low-resistance points in substations.
About the product
The PDRM-10A injects current through two conductors connected to the ends of the resistance being measured, while an independent circuit records the voltage drop with the voltage electrodes positioned inside the current electrodes. This four-wire arrangement, or Kelvin method, removes the influence of the resistance of the measuring cables.
The unit offers a standard measurement mode and a differential mode, with automatic shutdown to save battery power. The kit includes the micro-ohmmeter, a set of rechargeable NiMH batteries, a charger, the user manual and the calibration certificate.
Accessories available: probe for duck-elbow grounding connections, two-hand Kelvin clamps with interchangeable tips, booster-type and dolphin-type clamps, probe for testing exothermic welds, personal grounding tester, reference resistance, protective case and transportation case.
Technical specifications
| Measurement method | Four-wire (Kelvin), with automatic current injection from 5 mA to 10 A |
| Range and resolution | 0.01 µΩ to 200 Ω; resolution of 0.01 µΩ |
| Accuracy | ± 0.1% ± 2 digits on all scales |
| Display | 128 × 64 pixel backlit LCD |
| Power supply | 6 rechargeable AA NiMH batteries |
| Autonomy | Over 12,000 measurements at 10 A; over 10,000 at other currents |
| Operating conditions | -20°C to 50°C; 0 to 95% humidity, non-condensing |
| Weight and dimensions | 0.86 kg; 203 × 114 × 51 mm |
| Injection currents | 5 mA, 250 mA or 10 A DC, automatic selection |
| Scales | 8 scales, from 20 µΩ to 200 Ω; ± 0.1% ± 2 digits on each |
| Charging and storage | Charging from 0°C to 50°C; storage from -40°C to 50°C |
Frequently asked questions
Which micro-ohmmeter is best for measuring contact resistances and grounding joints in the field?
A four-wire instrument that resolves fractions of a micro-ohm, injects several amperes and is easy to carry. The PDRM-10A resolves 0.01 µΩ, injects up to 10 A DC with automatic current selection, keeps the reading stable near strong magnetic fields thanks to its filtered inputs and weighs 0.86 kg.
What is the difference between the PDRM-10A and the PDRM-1A?
Test current and resolution. The PDRM-10A injects up to 10 A DC and resolves 0.01 µΩ, with over 12,000 measurements at 10 A per charge; the PDRM-1A reaches 1 A DC and resolves 1 µΩ. Both measure up to 200 Ω with ±0.1% ±2 digits and weigh 0.86 kg.
What measurement method does the PDRM-10A use?
The four-wire Kelvin method: two conductors inject the current while an independent circuit measures the voltage drop, removing the influence of the measuring cables' resistance.
Can it be used near strong magnetic fields?
Yes. Its input channels are heavily filtered and an internal microprocessor compensates for thermocouples and parasitic voltages.
What resolution and accuracy does it offer?
It resolves down to 0.01 µΩ over a range of 0.01 µΩ to 200 Ω, with an accuracy of ± 0.1% ± 2 digits on all scales.
What does the factory kit include?
The micro-ohmmeter, a set of rechargeable NiMH batteries, a charger, the user manual and the calibration certificate.
